摘要：
Castor oil has been widely used in various fields due to its properties, leading to large attention for its extraction mechanism. To research the castor oil extraction mechanism during pressing, a self-developed uniaxial compression device combined with an in situ observation is established. The effects of pressure, loading speed, and creep time are investigated, and a finite element model coupling with multi-physics is established for castor oil pressing extraction, verified by the seed cake experimental compression strain matching with numerical simulation under the same condition. Simulation results indicated that the pressing oil extraction process can be divided into two stages, Darcy's speed shows the first sharp decreasing stage and the second gradual increasing stage during porosity and pressure interaction. In the first stage, porosity is dominant on Darcy's speed. With porosity decreasing, the pressure effect on Darcy's speed exceeds porosity in the second stage. With seed thickness increasing, Darcy's speed first increases and then decreases. With loading speed increasing, Darcy's speed increases. Darcy's speed decreases constantly with creep time increasing. This study can provide basic theoretical and practical guidance for oil extraction.
摘要：
Castor oil has attracted large attention for wide applications, including lubrication oil and bioenergy resources. Castor seeds mechanical pressing is widely used for oil extraction. To better research castor seeds mechanical-structural damage behavior and oil extraction mechanism during extrusion, a self-developed mechanical pressing test setup combined with in situ observation is built for oil output behavior. Influencing factors of working pressure, speed, temperature and creep time on oil outflow were investigated. The results indicate that seeds squeezing extraction can be divided into three stages, preloading, oil discharging, compressing consolidation stage, matching with pressing cake structural evolution. As working pressure increases, oil yield shows an upper parabola relation with pressure. When pressure exceeding 25 MPa, castor oil yield increasing tends to stabilize, reaching 38%. Speed effect showed down parabola relation on oil yield, opposite to stress factor. Creep time promoted oil output with upper parabola within 720 s. When temperature below 120 degrees C, a linear increasing relation on oil yield presents. Oil yield decreases when above 120 degrees C. This research provides in-depth theoretical guidance for industrial castor oil extraction.Practical ApplicationsCastor seeds are rich in oil content. Extracted castor oil has been widely used for industrial applications such as biodiesel, lubricants, medicine. Mechanical extraction working parameters optimization can improve oil yield of castor seeds. The research provides a basic working optimization for castor seeds oil extraction. Castor oil has unique properties and has been proved to be a high promising renewable and independent energy sources. Compared with solvent oil extraction, mechanical oil pressing extraction method has higher oil quality and safety. The mechanical extracted oil is pure without organic solvent. In the research, castor seeds compression-structural damage property and oil extraction mechanism were studied. Besides, the influence factors including compression pressure, speed, temperature and creep time are analyzed, working optimization for castor seeds oil extraction. The research provides important reference value for the mechanical pressing process and mechanical design of castor seeds in the practical applications. Using the self-developed mechanical pressing test setup and in situ observation technology, the castor seeds mechanical-structural damage behavior during the pressing process and oil extraction mechanism were analyzed, as well as the effects of pressure, speed, temperature, and creep time on the oil yield. image
